In U.S. Pat. Nos. 4,049,033, 4,010,783, 4,076,063, and 4,088,166 plus U.S. application Ser. No. 744,230, filed Nov. 23, 1976 now U.S. Pat. No. 4,090,541, among others, molded collapsible solution containers are shown which may be made out of a relatively stiff plastic, such as a copolymer which is predominantly polypropylene. Despite the relative stiffness of the bag material compared with, for example, a typical medical grade formulation of polyvinyl chloride, the bags are readily collapsible under a liquid suction pressure head on the order of three feet, so that the container may be effectively used for storing and dispensing parenteral solutions, blood or blood components, or the like.
The improved collapsibility of the bags of the above described patents and applications results from the as-molded tapered shape of the container, plus the use of opposed gussets near the shoulder portion defining beads of folding weakness, as well as other lateral beads of folding weakness about the shoulder, as described in the above reference.
In accordance with this invention, further improvements are provided to the containers described above, which result in an even greater reduction in the internal volume of the containers in their collapsed configurations, as well as improved tail seals over that which has been previously available for thin-walled, collapsible containers.